Ethernet Fragment Error Indication for Cut-Through Forwarding
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Solution Overview
Problem
In data transmission scenarios, especially in the Industrial Internet of Things and Internet of Vehicles, the use of chain or ring networks by forwarding devices often results in end-to-end delays and errors in Ethernet frames, which can go undetected due to the limitations of cyclic redundancy check (CRC) algorithms, especially when errors are numerous or occur across multiple forwarding devices.
Innovation Solution
A data transmission method where forwarding devices receive and process Ethernet frames by determining errors through frame check sequence (FCS) recalculations and changing fragment types to include error indication information, allowing physical layer circuits to detect errors without relying on CRC checks, thereby increasing error detection success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If cut-through forwarding technology is used to reduce end-to-end delay, then forwarding speed is improved, but error detection capability deteriorates because CRC checks cannot detect errors when they occur across multiple forwarding devices
Solution Approach 1:
The patent segments the error detection function from the traditional CRC mechanism by introducing independent error indication fields in Ethernet frames. Each forwarding device can independently set error indication bits when errors occur, allowing distributed error marking without requiring complete frame retransmission or complex end-to-end verification, thus maintaining high forwarding speed while improving error detection reliability.
Solution Approach 2:
The patent introduces an intermediary error indication mechanism that acts as a mediator between forwarding devices and error detection. Instead of relying solely on destination-based CRC verification, intermediate forwarding devices can directly mark errors in transit using error indication fields, enabling real-time error detection without disrupting the cut-through forwarding process.
2Device complexity
If traditional CRC check is used for error detection, then implementation simplicity is maintained, but error detection success rate deteriorates when large quantities of errors occur across multiple forwarding devices
Solution Approach 1:
The patent applies preliminary action by having forwarding devices proactively mark errors as they occur during the forwarding process, rather than waiting for end-to-end CRC verification at the destination. This preliminary error marking using error indication fields ensures errors are detected and flagged immediately, significantly improving detection success rate while maintaining implementation simplicity through straightforward field manipulation.
Solution Approach 2:
The patent changes the error detection parameter from binary CRC pass/fail to a multi-state error indication system where forwarding devices can set specific error indication bits based on the type and location of errors. This parameter expansion allows more precise error characterization and higher detection success rates while keeping the underlying implementation relatively simple through bit field manipulation.
Data Source
AI summary
A method includes a network device receiving a plurality of fragments of an Ethernet frame, where the plurality of fragments include an initial fragment and a first fragment, and where the initial fragment includes a destination media access control (MAC) address field. In response to an error occurring in the Ethernet frame, the first fragment is changed to a second fragment, where the second fragment includes second type indication information (TII) and second to-be-transmitted data (TBTD), where the second TII indicates that a type of the second TBTD is a control character, where a value of first TBTD is different from a value of the second TBTD, and where the second TBTD indicates that an error occurs in the Ethernet frame. The network device sends the second fragment to a destination device.